如何检查unique_ptr是否指向this

Question

在遵循代码的和平，我试图找到另一个对象，具有相同的坐标作为this。如何正确地做呢?

auto& organism_vector = world->get_vector();
auto attacked_organism = find_if(begin(organism_vector), end(organism_vector), [this](const unique_ptr<Organism>& attacked_organism)
{
return this->get_coordinates() == attacked_organism->get_coordinates() && *this != *attacked_organism;
});

另一件事，当我终于设法得到这个迭代器，如何引用攻击有机体类方法?

*attacked_organism.get_coordinates();

Answer 1

将*this != *attacked_organism改为this != attacked_organism.get():

auto& organism_vector = world->get_vector();
auto attacked_organism = find_if(begin(organism_vector), end(organism_vector),
[this](const unique_ptr<Organism>& attacked_organism)
{
return this->get_coordinates() == attacked_organism->get_coordinates() && this != attacked_organism.get();
}
);

一旦你有find_if()返回的iterator(并且在你验证它不是end迭代器之后)，你可以在Organism上调用方法，首先对迭代器解引用以访问持有Organism*指针的unique_ptr，然后对unique_ptr解引用以访问Organism本身:

auto attacked_organism = find_if(...);
if (attacked_organism != end(organism_vector))
{
(**attacked_organism).get_coordinates();
or:
(*attacked_organism)->get_coordinates();
...
}

---

附带说明:我不建议给迭代器变量与lambda参数相同的名称。这只会让人看不懂。lambda试图找到要攻击的Organism，但它实际上还没有受到攻击，因此您应该更适当地命名lambda参数，例如:

auto attacked_organism = find_if(begin(organism_vector), end(organism_vector),
[this](const unique_ptr<Organism>& candidate_organism)
{
return this->get_coordinates() == candidate_organism->get_coordinates() && this != candidate_organism.get();
}
);

对于这个问题，我也不建议将迭代器命名为attacked_organism。它不是实际的Organism，它是iterator到Organism，所以更像这样的东西会更容易读:

auto& organism_vector = world->get_vector();
auto found_iterator = find_if(begin(organism_vector), end(organism_vector),
[this](const unique_ptr<Organism>& candidate_organism)
{
return this->get_coordinates() == candidate_organism->get_coordinates() && this != candidate_organism.get();
}
);
if (found_iterator != end(organism_vector))
{
auto &attacked_organism = *found_iterator;
attacked_organism->get_coordinates();
...
}